They are not legal if they do not have the Copyright owner's permission to distribute.
Remember: we are not talking about old games here, these sellers are preloading Hard Drives with a WHDLoad Key and re-selling it over many times. WHDLoad is an excellent piece of software that is regularly updated and the author does not deserve to have his work pirated. They are also reselling Workbench and AmigaOS files without permission.
These sellers are selling their CF hard disks at a price of nearly double the market price. The sellers in question are selling sufficient quantities to be considered a business by the tax authorities but are not registered as a business, not paying taxes and have little interest in providing after-sales support. We have had dozens of phone calls from their customers to us asking for help.